Outcome evaluation of rehabilitation therapy in general, and cancer patient rehabilitation in particular, is problematic because of a lack of valid and reliable measures. This study addresses problems of measuring one aspect of rehabilitation--physical functioning. Traditionally, an index of Activities of Daily Living (ADL) has been used to assess physical functioning. Despite widespread application, ADLs in use lack unity of conceptual basis, content, and implementation procedures. Initially, this study sought to clarify the conceptual background of ADLs through a national survey of over 2,000 rehabilitation professionals (physiatrists, physical therapists, occupational therapists, rehabilitation nurses). Three issues were addressed in this survey: 1) specification of important functional categories in the assessment of overall physical functioning; 2) specification of the minimal combination of component tasks for adequate assessment of each functional category; 3) determination of the degree of unity in the conception of overall physical functioning among rehabilitation professionals. Preliminary analysis suggests substantial unity of this concept. Further analyses to resolve above issues are in process. Alternative strategies will be developed for scoring, weighting and aggregating the resultant measure. A second national survey of rehabilitation professionals will be conducted to identify the optimal strategy, considering ease of implementation, clinical significance and sensitivity of the measure to small changes in functional levels of patients.